Electrical stimulation of the body is an increasingly important medical procedure. For example, the circumstances in which the well known cardiac pacemaker is employed have expanded considerably. Other electrical stimulators are similarly gaining in acceptance.
A difficulty encountered in many stimulating contexts is the requirement that the electrode be precisely positioned and that that position be maintained. For example, nerve stimulation is often selective requiring precision in the placement of the electrode. A later movement of the electrode is destructive to the effectiveness of the stimulation and may render the stimulation totally ineffective.
In some contexts, it is possible to secure the electrode in the desired position. In others, securement is not possible. In all contexts, forces acting on the lead may be transmitted by the lead to the electrode. Particularly in those contexts where the electrode is not secured, such forces have a tendency to displace the electrode. Such forces are commonly experienced and result from such factors as body movement, muscle contraction, etc.
Many surgeons have evolved their own techniques for anchoring a lead to reduce the transmittal of a displacing force to an electrode. For example, it is known that many surgeons employ a deformable surgical clip to anchor a body stimulator lead. The clip is positioned around and drawn down on the lead. The clip also engages body tissue. In this manner the lead is secured to the body tissue. Other techniques employ the use of a band positioned around the lead body as a suturing device.
An improvement to the techniques described above is disclosed in U.S. Patent Application Ser. No. 926,105 filed July 19, 1978, now abandoned for Lead Anchoring Device, in the name of Duane J. Zytkovicz, which is commonly owned with the present invention. In the referenced application, a simple molded device is disclosed which can be positioned anywhere along the lead body and which securely engages the lead body and may be easily anchored to body tissue thereby providing a simple and reliable anchoring device. However, use of this device, and the techniques described above, may not be adequate in many situations. For example, in those contexts where it is not possible to secure the electrode it is unlikely that the lead can be anchored at a position sufficiently close to the electrode to adequately isolate the electrode from extraneous forces imparted to the lead body. Therefore, while lead anchoring is a helpful procedure in maintaining the position of an electrode, it, in itself, is not always adequate.